Research: Dairy milk may be critical to global nutrition

As the world aims for a 2050 net zero future, the dairy industry is working to reduce its environmental impact to achieve that goal, with research currently focused on greenhouse gas mitigation strategies that do not compromise animal health and production. Many discussions maintain that a radical transformation — involving reducing animal-based foods and increasing plant-based foods — is needed in agriculture in order to meet climate goals.

Researchers from Virginia Tech’s School of Animal Sciences are working to understand the trade-offs of this transformation. Their study, published in the Journal of Dairy Science, aims to understand the holistic impact of the dairy industry, quantifying the contribution of dairy milk to human nutrition, along with associations with agricultural greenhouse gas emissions and water use.

Robin R. White, the study’s lead investigator, said global-scale assessments of the trade-offs associated with dairy production are required to understand the role dairy plays in feeding the globe.

Previous investigations of the environmental footprint of dairy systems have reported on dairy’s contribution of critical vitamins and minerals to human health and have often presented outputs in terms of milk weight or energy/protein content only.

“We were interested in using network analysis methods to better understand the trade-offs between nutrition and environmental impact in the existing food systems, globally,” White said.

White and co-author Claire B. Gleason started with data collected by the United Nations Food and Agriculture Organisation, allowing them to evaluate data at country and continent levels. They were able to quantify global supplies of different foods and the environmental impacts of these systems.

The data was leveraged to better consider global-scale contributions of fluid milk to human nutrition and the environmental impacts of food production, specifically emissions and water use. Foods were only considered in their pre-processed forms and fluid milk from each dairy species was included. Total food supply was calculated using a definition accounting for loss, waste, trade and animal feed. These figures were used as a reference supply of food that could be consumed by humans, factoring in nutrient requirements based on age and gender.

To understand how milk and meat products are associated with agricultural environmental impacts, supplies were correlated with greenhouse emissions and blue water withdrawal for watering crops and livestock, using individual country data.

The data demonstrated how critical milk is within the global agroecosystem and to the nutritional adequacy of foods produced from that system. Despite environmental trade-offs associated with milk production, it is an essential source of vitamins and minerals such as protein, riboflavin, vitamin B12 and phosphorus.

“Indeed, milk is one of the only low-energy sources of calcium available for human consumption, and our results suggest that 35% of the calcium available for human consumption globally is obtained from milk,” White said.

Regardless of income level, calcium is among the most inadequately consumed essential micronutrients.

The authors said there are several limitations to the analysis and more research is needed to find outside-the-box solutions, so the study is best viewed in complement with broader research on the topic.

Considering these limitations, improving global milk availability, including coordinating distribution of milk among supply chains, may be important priorities for enhancing availability of critical nutrients within food systems worldwide.

Image credit: iStock.com/bymuratdeniz